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Deoxyribonucleic acid(DNA) is a folded-chain mechanism explaining the mysterious questions of evolution about the living organisms on Earth, according to the molecular basis of life. The genetic instructions of the structure of the living organisms and the information of the adaptations to the environment are the part of the huge amount of data conveyed by DNA. DNA replication is the name of the biological process of producing two identical DNA molecules within the encoded data of the original one.

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Nucleotides, proteins, lipids, carbohydrates, hydrogen bonds and phosphate are the constitutive chemical compounds of the helix-structure of DNA. The helix-structure of DNA is composed of a twisted DNA strand bonded to another, each of these strands is separated from each other and used as a template to synthesize a new strand for replicating DNA by DNA polymerase, which is an enzyme catalyzing a chemical reaction to copy the original molecule, during DNA replication. This process is also called Semi-conservative replication. Nucleotides are composed of a nitrogenous base, a pentose (deoxyribose or ribose) and a phosphate group. The nitrogenous base is a chemical compound that consists of at least one nitrogen atom at its base, and they are widely called the nucleobases due to their relation with nucleic acids. Primary nucleobases are adenine(A), cytosine(C), guanine(G), thymine(T) and uracil(U) which makes base pairs with adenine(A) in RNA, instead of thymine(T). Nucleobases divided into two groups, adenine(A) and guanine(G) are purines(heterocyclic aromatic organic compound ), and thymine(T), cytosine(C), uracil(U) are pyrimidines(aromatic heterocyclic organic compound). A base pair is a purine (two carbon-nitrogen rings) bonding a pyrimidine (one carbon-nitrogen ring). Pentose(five-carbon sugar) is a monosaccharide, which is the most basic unit of carbohydrates, consisting of five carbon atoms. Furthermore, nucleic acids are derived from monosaccharide compounds including deoxyribose and ribose, therefore DNA and RNA are aberrations for Deoxyribonucleic acid and Ribonucleic acid. Phosphate is an inorganic chemical occurred by the chemical reaction between Phosphorus and Oxygen.

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The electromagnetic force was the reason for occurring base pairs, nucleotides, nucleosides, pentoses, phosphates and nucleobases naturally on Earth. There are four fundamental interactions (also known as fundamental forces), the strong interaction, the weak interaction, the gravitational interaction and the electromagnetic interaction. The electromagnetic interaction occurs between electrically charged particles and all interactions between electrically charged particles, such as atom nuclei and electrons, can be explained by the electromagnetic force. Electric charge divided into two types, negative and positive, and carried by subatomic particles(proton or atom nuclei and electrons). Positively charged particles are bound to negatively charged particles by the electromagnetic force, hence the chemical bonds(ionic and polar covalent) between atoms, ions and molecules are strong enough to hold them together. A chemical bond occurs as an attraction in oppositely charged ions or atoms sharing electron pairs. Ionic bonds occur between oppositely charged ions(negative and positive), atoms have gained more electrons is a negatively charged ion(widely called anion) and which have lost one or more electron is a positively charged ion(widely called cation). On the other hand, covalent bonds(also known as molecular bonds) occur between atoms sharing electron pairs which are also called bonding pairs. Atoms losing or gaining electrons need to make their valence shells whole again to become stable, according to the Octet rule. In order to get this kind of stability, atoms shares one(single covalent bond) or more(multiple covalent bonds) electron pairs with each other. Electronegativity is the ability to attract electrons and causes of forming a polar covalent bond between atoms that is lead to the formation of a hydrogen bond between molecules.

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DNA is held together by covalent bonds(carbon-nitrogen bonds), polar covalent bonds and hydrogen bonds(which are between base pairs). Each of the folded-strand of DNA consists of phosphates, pentoses, nucleobases strongly bound with covalent bonds to each other. The helix-structure of DNA is due to nucleotides bonding with hydrogen bonds to each other. Furthermore, the bending flexibility of DNA is due to its covalent bonds and its hydrogen bonds. DNA replicates itself precisely because of the hydrogen bonds between base pairs(two hydrogen bonds forming between adenine and thymine, and three hydrogen bonds forming between guanine and cytosine). The steps of DNA replication proceeds via the electromagnetic force, hence DNA is the inevitable consequence of the electromagnetic force.